Garden Talk: May 19, 2011

From NGA Editors

The Perils of Prenatal Pesticide Exposure

More and more evidence is accumulating on the harmful effects of pesticides, herbicides, and other chemical hazards, especially on the health and development of our children. Three recently published studies have shown a link between prenatal exposure to organophosphate pesticides and lowered IQ in children between the ages of six and nine. One of the primary means of exposure is through pesticide residues on food.

Buying organically grown fruits and vegetables is one way to help limit exposure, but for some families, buying all organic may present a considerable financial burden. In an effort to help folks make the safest, most economical choices when it comes to buying produce, the Environmental Working Group (EWG) has compiled a list of its Dirty Dozen, the twelve kinds of fruits and vegetables that are most likely to have the highest pesticide residues and the ones toward which they suggest putting your dollars first for organically grown choices. They also list the Clean 15, the produce least likely to contain residues and therefore safer to purchase when conventionally grown.

But there is another great way to get safe produce economically and that is to grow your own. Among the fruits and veggies that made the Dirty Dozen list are some great choices for growing in the home garden, including bell peppers, spinach, kale, and potatoes, along with strawberries and blueberries. When you raise them yourself, you'll know that these fruits and vegetables are not only as fresh and nutritious as possible, but that they are free of any harmful residues as well.

Don't Reach Back

Are you one of those shoppers who reach into the back recesses of the produce display hoping to find the freshest salad greens with the latest expiration date? Well, it turns out that grabbing what's out in front may be not only easier, but better for you.

In research led by postharvest plant physiologist Gene Lester at a USDA Agricultural Research Service laboratory in Texas, scientists discovered that spinach leaves exposed to continuous light during storage were actually higher in nutrition than those exposed to continuous darkness. The spinach leaves that were exposed to light continued to photosynthesize, resulting in significant increases in the levels of carotenoids, vitamins C, E, and K, and folate, compared to the non-light exposed leaves. Researchers did note some more wilting after three days in light-exposed flat-leaved types of spinach relative to crinkle-leaved varieties, but the nutritional value of both was enhanced.

This research may suggest ways for markets to store and display salad greens to maximize their nutritional potential. In the meantime, make your shopping a little quicker -- and healthier -- by reaching for up-front greens. Better yet, for the highest nutritional value, grow your own!

For more information on how market lighting affects nutrients, go to: ARS.

Blueberries against Breast Cancer?

Can the fruits you eat while pregnant have a beneficial effect on your children years into their lives? That's the question that Rosalia Simmen and co-investigators at the Arkansas Children's Nutrition Center Breast Development Laboratory in Little Rock are hoping to answer with their research into the effects of blueberry powder on the normal mammary gland development of mice.

They found that when the dams (mother mice) were fed food containing 5-percent blueberry powder while they were pregnant and nursing their pups, their female offspring showed improvement in several indicators of rat mammary gland health, including branching of the gland and levels of a tumor-suppressing protein called PTEN.

While there have been other lab animals studies indicating a link between blueberries and breast cancer prevention, this is the first to show a link between the mother animal's blueberry consumption and healthy breast development in her offspring.

These health benefits have not been demonstrated in humans yet, and further research is needed see if these effects hold true for more than mice. But Simmen notes "The study provides strong support for the idea that early exposure, even in the womb, to healthy eating may profoundly affect the health of the unborn child. In short, you are what your mother eats."

Given all the other well-documented benefits of adding this high anti-oxidant fruit to your diet, consider adding some of these easy-to-grow fruits to your home garden for a harvest of delicious, healthful berries.

Suburban Lead

Common wisdom had it that gardeners growing plants in urban areas are the ones who need to be worrying about high levels of lead and other heavy metals in their soils. But some recent research by Iowa State University agronomists on soils in a suburb of Des Moines suggests that this problem may be more widespread than previously thought.

Researchers took soil samples from suburban residential areas that had been developed at various times from before 1939 up to 2005. They found that the average concentration of lead was even higher than had previously been reported for urban Des Moines, with the older sites having the highest levels, and in some cases higher than the maximum concentration considered "normal." They also found that more recently developed sites had lower levels, which was attributed to the phasing out of leaded gasoline for on-road vehicles in the U.S. by 1996. In the particular area studied, they also found that average concentrations of other heavy metals such as zinc and cadmium varied with the age of the development.

What this suggests is that, no matter where you garden, it's a good idea to start by having a soil test done that includes testing for heavy metals. Then you'll not only know the pH and nutritional status of your soil, you'll also be aware of any possible contamination problems. Your state Cooperative Extension Service or Master Gardeners Program can tell you how to go about submitting a soil sample for testing for minimal fee.